Legionella in Food Processing: The Invisible Threat to Your Facility and How to Manage It

Legionella hides in the same utility systems that keep production running. It grows in warm, stagnant water and spreads through fine mist. In food and beverage plants, that means cooling towers, hot water systems, humidifiers and misters can turn into business risks without a tight plan. The fix is straightforward — build a practical water program, test wisely and partner with a service team that guarantees results.

Why Food Plants Should Care

Food and beverage facilities use complex water systems that can generate aerosols. Public health agencies point to cooling towers and large plumbing systems as common sources for legionella exposure. The Centers for Disease Control and Prevention (CDC) explains that people get Legionnaires’ disease by breathing in mist containing the bacteria, not from person-to-person contact.

In August 2025, the New York City Health Department reported a Central Harlem cluster tied to multiple cooling towers. The city ordered rapid remediation, used polymerase chain reaction (PCR) for quick screening and confirmed results with culture, which remains the gold standard. That response mirrors what well-run plants do inside the fence line.

Regulators also consider legionella a workplace hazard. The Occupational Safety and Health Administration (OSHA) can invoke the General Duty Clause when employers fail to control recognized waterborne risks, so documented controls matter for safety and compliance.

Where the Risk Shows up in a Plant

Image source: https://www.chardonlabs.com/about-us/core-capabilities/

A short, shared risk map helps operations, maintenance, and environment, health and safety (EHS) work from the same page. Focus on systems that combine warm water, nutrients and the chance to aerosolize droplets.

• Cooling towers and evaporative condensers near air intakes or traffic lanes
• Potable hot and cold water feeding sanitation points, eyewash stations and locker rooms
• Humidifiers, foggers and misters used for product quality or comfort
• Ice machines and decorative features in cafeterias or public spaces

CDC’s control toolkits cover these sources with practical steps any facility team can adopt.

Legionella Testing Explained

Legionella testing validates control, but it does not replace it. Keep the approach clear and actionable for line leaders and technicians.

Here’s what to use and why:

• Culture confirms live legionella and supports investigations. It takes up to two weeks, but it tells you what grows.

• PCR/qPCR gives fast results to guide immediate actions. Use it to screen and decide whether to clean, disinfect or adjust feed.

NYC Health’s investigation uses exactly this sequence — PCR to move fast, culture to confirm — because it balances speed and certainty. Plants can follow the same logic for routine legionella testing in towers and high-risk plumbing.

How to Act on Results

Define simple action bands in your water management program (WMP). For example, a “watch” band triggers inspection and trend review, while a “remediate” band triggers cleaning, disinfection and retesting. CDC’s WMP toolkit lays out the elements to set those bands and prove they work.

Control That Operators Can Run

Strong programs do three things well — they put owners in control of each control point, track a few critical readings that predict trouble and keep the documentation tight so audits move quickly. Use the CDC WMP model as the backbone, then adapt it to plant realities so supervisors can own daily checks without guesswork.

How a Treatment Plan Flows

Start with a map of your water systems and rank them by aerosol potential and proximity to people or products. Tie each system to clear control limits, like temperature ranges for hot water or cycles and disinfectant targets for cooling towers. Then monitor what matters, such as temperature, cycles, conductivity and disinfectant levels.

When a reading drifts or legionella in a water sample crosses a band, take a defined action, record it and schedule a retest. That loop — map, control, monitor, validate — makes the program easy to run and defend.

Red Flags That Raise Risk

Teams spot problems faster when they know the signals to watch. These cues appear across plants and seasons and often precede legionella positives.

• Warm, stagnant sections of pipe or equipment that sit idle for days
• Cooling tower cycles or conductivity that swing outside the normal band
• Inconsistent disinfectant feed or automation that alarms without follow-through
• Gaps in service notes, sampling dates or corrective action records

CDC’s toolkits and outbreak investigations repeatedly point to these conditions as drivers of growth and spread.

Where a Partner Makes the Difference

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Many providers sell drums and stop by on a route. That model leaves facility teams juggling alarms, logs and sampling independently. Food plants need a service partner who aligns with production uptime, audit readiness and verified legionella risk management — not just chemical volume.

Chardon Labs stands out because it sells “clean systems,” not chemicals, with guaranteed annual pricing and ISO-certified technicians. The company’s own language says it plainly — “We don’t sell chemicals, we sell clean systems.”

Pair that stance with electronic service reporting and remote monitoring, and you get a program built for speed, visibility and accountability.

• Proven compliance support: Service managers hold ASSE 12080 legionella credentials and follow ASHRAE Standard 188 guidance when they build WMPs and sampling plans. That gives safety and QA teams the documentation regulators expect.

• Guaranteed results and predictable costs: ISO practices and a guaranteed annual price align incentives with your OEE and budget, not chemical consumption.

• Faster decisions with better data: Electronic service reports arrive the same day, and remote monitoring tracks parameters like conductivity, flow, pH and alarms, which shortens time to action.

How Chardon Lab’s Approach Compares

This side-by-side shows how Chardon’s service-first model differs from a typical chemical supplier across the factors that matter most to plants — uptime, compliance and cost.

A Practical Path for Testing and Control

Facility leaders succeed when they translate standards into routines the team can run. Use this plain-language sequence so everyone understands their role.

1. Map and Prioritize

Walk the system with operations and maintenance. Identify towers, hot water loops, humidifiers and any device that can aerosolize water. Rank them by exposure to people and products. Align that list with the CDC WMP toolkit so your plan mirrors public health best practice.

2. Control and Monitor

Hold temperature targets in hot water loops, run towers at steady cycles and calibrate feed equipment. Track a few readings that predict problems and record them in the same place every time. Remote monitoring can surface drift faster than manual checks.

3. Validate and Improve

Schedule routine legionella testing methods appropriate to each system — use PCR for quick screens when risk rises and culture to confirm control. When results cross an action band, clean, disinfect and retest until the trend returns to baseline.

What “Good” Looks Like in a Food Plant

Stable towers run at target cycles with few alarms. Potable recirculation holds temperature without big swings. Service reports show clear tasks, proof of completion and follow-ups.

When public health events happen nearby, your team already knows who to call, how to sample and how to verify remediation. CDC’s surveillance and NYC’s current response reinforce that simple, documented practices quickly reduce risk and keep people safe.

The Business Case for Chardon Labs

Chardon’s model lines up with food industry priorities, including fewer surprises, stronger compliance stories and better utility performance.

• Best for regulatory readiness: ASSE 12080 credentials plus ASHRAE 188-aligned WMPs support inspections and incident reviews.

• Best for cost control: Guaranteed annual pricing and monitoring limit waste and unplanned maintenance.

• Best for results: ISO workflows, electronic reporting and remote data help teams solve issues before they hit production.

That combination makes legionella treatment part of a wider reliability program, not a one-off chemical purchase.

Next Steps to Reduce Legionella Risk

Set one target — a running WMP that your operators understand and your auditors can follow. Use CDC’s toolkit, schedule routine legionella testing and partner with a service provider whose incentives match yours. Chardon Labs’ “clean systems” commitment, ISO-certified technicians and remote monitoring give plant teams the confidence to keep water systems boring in the best possible way. Add that to your reliability dashboard and treat legionella risk management like any other performance KPI. Contact Chardon Labs today to reduce the risk at your food production facility.